400EX idle problem

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10-22-2012 | 08:41 PM

savage5480

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From: tennessee

400EX idle problem

When my 400ex idles it starts to rev high then low then high and low and so forth. I have a hmf slip on exhaust and have not jetted. Iam not sure if that is the problem or not.

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10-22-2012 | 09:26 PM

jgar

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From: Gardner ma.

You will want to rejet. But it sounds like its sucking air. Make sure the carb is fully seated and tight in the boot.

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10-23-2012 | 06:46 PM

jgar

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From: Gardner ma.

Does the plug look like its running lean?

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10-24-2012 | 01:04 PM

savage5480

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From: tennessee

Quote:

Originally Posted by jgar

Does the plug look like its running lean?

How can you tell if it is running lean?

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10-24-2012 | 07:16 PM

jgar

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From: Gardner ma.

The tip of the spark plug will look white.

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10-29-2012 | 06:59 PM

savage5480

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From: tennessee

Quote:

Originally Posted by jgar

The tip of the spark plug will look white.

It is a greyish brown color.
Or light brown

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